Question: Simplify the following expression: $a = \dfrac{5}{z + 1} \div \dfrac{5}{7z}$
Answer: Dividing by an expression is the same as multiplying by its inverse. $a = \dfrac{5}{z + 1} \times \dfrac{7z}{5}$ When multiplying fractions, we multiply the numerators and the denominators. $a = \dfrac{ 5 \times 7z } { (z + 1) \times 5}$ $a = \dfrac{35z}{5z + 5}$ Simplify: $a = \dfrac{7z}{z + 1}$